The study of stem cells and their potential, as well as the development of techniques that allow their manipulation and application in health, is one of the latest and most promising discoveries of the science to cure a lot of diseases of the modern society.
Stem cells are undifferentiated cells, in other words, they don't have a specific function. They can turn into several different cell types, through a process called "differentiation." They are capable of dividing and renewing themselves for long periods, and they can give rise to specialized cell types. Its main feature is the ability to develop into several types of tissues that constitute the human body. They can be of two types: embryonic or adult. The embryonic ones are those that are removed from the animal still in the embryo phase. As a main characteristic, they are a big capacity to become any other cell type. Adult stem cells can be found in several parts of the human body. The most commonly used for medicinal purposes are the cells of the umbilical cord, of the placenta and of the bone marrow. For besides the bone marrow, other tissues where we can extract adult stem cells are retina, cornea, pulp gums, skin, liver, gastrointestinal tract and pancreas. Because they are extracted from the own patient, they offer small rejection risk in medical treatments. The main disadvantage of adult stem cells in relation to embryonic stem cells is their smallest transformation capacity.
Scientists have been trying to find the cure for several diseases - Parkinson, Alzheimer, stroke, diabetes, heart disease and even paralysis - using stem cells, especially embryonic cells but in many countries, legal impediments exist for the use of these cells and some other countries don't have explicit laws to regulate research on human stem cells.
Because of these impediments, stem cells have more used have been the adult ones, found in adult's bone marrow, which have the potential to differentiate into different cell lines. These cells have the ability to self-renew during a lifetime of the organism.
It has been having investigations in order to manipulate adult stem cells to differentiate into cells of different tissues such as nervous cells, brain, liver and heart.
The researches in the treatment and cure of diseases with stem cells have been revealing auspicious. Here's good news, which brings hope to people who are blind or having reduced vision, published in Jun 3, 2009 in the article "Stem Cell Contact Lenses Cure Blindness in Less Than a Month" by Adam Frucci. It was restored the sight of three persons, two blind of one of the eyes and one with very low vision in one of the eyes, in less than a month, with contact lenses coated with culture of stem cells.
They were extracted stem cells from healthy eyes, which were grown in contact lenses for 10 days and then put in the respective ones patient. In the period of 10 to 14 days of use, the cells began to colonize and to repair the cornea.
The degree of recovery of the vision in these three patients was not same. Those with total blindness started to get to read large letters while the third patient, who had still some vision capacity, passed to see normally.
The research team is encouraged with the results but is still cautious: they still remain doubts as to know the correction of vision will be permanent. For now, it is encouraging that the patients have been not only recovered the vision but also they have maintained the recovery of the vision to the date of publication of the article (18 months after intervention).
The simplicity of the technique and its low cost will allow that eventually it is carried out in countries with low resources.
It seems that we can have hope that the stem cells are in the future the cure, if not for great part of the diseases, at least for some.